1. Field of the Invention
This invention relates to data backup, and more particularly to apparatus and methods for providing near continuous data protection in a space-efficient manner.
2. Background of the Invention
Data is often one of an organization's most valuable assets. Accordingly, it is paramount that an organization regularly back up its data, particularly its business-critical data. Statistics show that a high percentage of organizations, as high as fifty percent, are unable to recover from an event of significant data loss, regardless of whether the loss is the result of a virus, data corruption, physical disaster, software or hardware failure, human error, or the like. At the very least, significant data loss can result in lost income, missed business opportunities, and/or substantial legal liability. Accordingly, it is important that an organization implement adequate backup policies and procedures to prevent such losses from occurring.
Various different solutions exist for backing up an organization's data. One solution, referred to as near continuous data protection, involves taking periodic snapshots (point-in-time copies) of source data at fixed intervals, such as 1-hour or 24-hour intervals. If data is corrupted or lost, a snapshot may be used to restore the data to the state that existed when the snapshot was taken. Although effective, one disadvantage of this technique is that, as snapshots accumulate, the snapshots may consume significant amounts of storage space. This problem may be exacerbated by decreasing the time between snapshots (thereby increasing the number of snapshots), or by increasing the amount of time that snapshots are accumulated prior to deletion. A large number of snapshots can also negatively impact the I/O performance of the source data since, depending on the point-in-time-copy technology used, the snapshots may need to be updated when writes are performed to the source data.
In view of the foregoing, apparatus and methods are needed to more efficiently provide near continuous data protection. Ideally, such apparatus and methods will reduce or minimize the storage space consumed by snapshots of the source data. Further needed are apparatus and methods to reduce or minimize the I/O performance impact on the source data. Yet further needed are apparatus and methods to quickly restore data from a snapshot when needed.